Introduction: Mechanical Insufflation Exsufflation (M-IE) and Lung Volume Recruitment (LVR) are two airway clearance devices that augment cough strength in Amyotrophic Lateral Sclerosis (ALS) (Senent et al., 2011). Changes in respiratory measures, morbidity, physical function and outcomes following prescription of M-IE and LVR require investigation. The characteristics of participants prescribed M-IE and LVR devices and their experiences with these devices has not been reported.
Objectives: The primary aim was to measure respiratory muscle function, in particular cough strength, chest infection morbidity, physical function and outcome in an Irish ALS cohort over one year. The second aim was to examine prescription practices in relation to M-IE and LVR and to compare participant characteristics in those prescribed these devices to those who were not. The third aim was to evaluate the experiences of participants who were prescribed M-IE and LVR.
Methods: A prospective longitudinal study assessed 108 participants at several time points over one year. Respiratory measures, including Sniff Nasal Inspiratory Pressure (SNIP), Slow Vital Capacity (SVC) percent predicted, Peak Cough Flow (PCF), physical function measured using the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R) and outcomes including chest infection rate and mortality were measured. Participant characteristics were evaluated at device prescription and a 13 item self-administered questionnaire evaluated their experience and usability with M-IE and LVR.
Results: Participants including 85 spinal onset and 23 bulbar onset patients, of mean age 62.05±11.47years were recruited. All measures including SNIP, SVC percent predicted, PCF and ALSFRS-R declined significantly (p<0.001) at a rate of 18.72cmH2O, 17.49%, 124.84L/min and 9.62 units per year respectively. One third reported a chest infection and 19.44% died. The rate of prescription of a device during the one year study period was 29.63% (32/108). Slightly more LVR devices (18, 56.3%) than M-IE devices (14, 43.8%) were prescribed. Participants prescribed a device had significantly lower average SNIP, SVC percent predicted, PCF and ALSFRS-R (p<0.001). Site of onset and time from diagnosis was not significantly different to participants not prescribed a device. Results of the questionnaire indicated that M-IE and LVR were user friendly; with a high level of adherence reported. Additionally, M-IE and LVR increased self-reported cough strength, although there was a low level of agreement that the devices increased speech volume and the self-reported increase in cough strength during a chest infection was undetermined.
Conclusion: The significant rate of decline of SNIP, PCF, SVC percent predicted and ALSFRS-R is consistent with previous reports. M-IE and LVR were frequently prescribed and participants prescribed these devices had lower respiratory function and ALSFRS-R scores. ALS participants report a positive experience with M-IE and LVR use and M-IE and LVR are user friendly.
References: Senent, C., Golmard, J. L., Salachas, F., Chiner, E., Morelot-Panzini, C., Meninger, V., Lamouroux, C., Similowski, T. & Gonzalez-Bermejo, J. 2011. A Comparison of Assisted Cough Techniques in Stable Patients with Severe Respiratory Insufficiency Due to Amyotrophic Lateral Sclerosis. Amyotroph Lateral Scler, 12, 26-32.
Ethical Approval: Ethical approval was obtained from Beaumont Hospital Ethics Committee and RCSI Research Ethics Committee.
Acknowledgements: Funding was provided by Research Motor Neurone
